The present invention relates generally to male contraception and more generally to devices and methods for reversibly occluding the vas deferens of a male.
Sterilization is the most popular method of contraception in the United States among couples with children and no desire for more children. It is believed that the acceptance of male contraception would improve if the procedure were more likely to be reversible. At present the surgical reversal of a vasectomy is problematic and requires microsurgery.
Various techniques have been applied to occlude the vas to achieve reversible contraception. For example, exterior clips have been used to xe2x80x9csqueeze offxe2x80x9d the lumen of the vas. However, it has been found that the pressure levels required for reliable occlusion promotes tissue necrosis. Injectable plugs have been used to xe2x80x9cfillxe2x80x9d the vas. However the delivery of the filler material is difficult and the curing time lengthens the procedure time. These xe2x80x9cformed-in-placexe2x80x9d plugs have also proved prone to migration which is undesirable.
The use of an inserted plug for vas occlusion is known from U.S. Pat. No. 4,512,342. The patent disclosed a pair of plugs, which are inserted through two closely, placed incisions in the vas. The plugs are tethered together and a portion of the tether is external to the vas lumen. The plugs are inserted with the aid of a stylus.
Published literature describes the evolution of the device and both single and double plugs were explored during development. Various anchor techniques and xe2x80x9cno anchorsxe2x80x9d were tried. This design process resulted in the product described in the patent. Although the device is safe and effective there is a continuing need to improve both the implanted device and the methods and apparatus used to implant the device.
According to the preferred methods of the invention, a pair of plugs called intra vas devices (IVD) are inserted through one or two holes in the vas. Each IVD has a hollow tubular body with a blunt and sealed end. A delivery device is provided to stretch the plug to both extend its length and to reduce its diameter. Although it is difficult to quantify, it is important to note that the IVD is very stretchable and flexible. A mandrel like core or stylus called a xe2x80x9cstyletxe2x80x9d extends through the IVD to engage the blunt end of the IVD. A release feature on the stylet device allows the physician to release the tension on the IVD plug to deploy the plug once it is positioned in the vas. One version of the stylet delivery device has a set of spring loaded jaws which engage the IVD plug at its proximal end. The release feature releases the jaws so the plug may assume a xe2x80x9crelaxedxe2x80x9d shape in the vas. Another version of the device uses tension on tether to stretch the IVD.
A sizer/dilator is used to both dilate the vas and to measure the internal diameter of the vas. Although this sizer step is optional it is preferred as an aid to selecting the correct diameter of plug. In operation, the optimal procedure sequence is to exteriorize the vas using a conventional surgical approach. Then, while holding the vas outside the scrotum a small puncture, incision or xe2x80x9cnickxe2x80x9d is made in the vas to create a surgical opening. Next the size/dilator is introduced to measure and dilate the lumen of the vas. With this information at hand the physician can select the appropriately sized IVD to load onto a stylet delivery device.